EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)

CERN-EP-2020-038LHCb-PAPER-2020-004

04 June 2020

Observation of new Ξ0c baryonsdecaying to Λ+c K

−

LHCb collaboration†

Abstract

The Λ+c K− mass spectrum is studied with a data sample of pp collisions at a centre-

of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb−1

collected by the LHCb experiment. Three Ξ0c states are observed with a largesignificance and their masses and natural widths are measured to be

m(Ξc(2923)0) = 2923.04± 0.25± 0.20± 0.14 MeV,

Γ(Ξc(2923)0) = 7.1± 0.8± 1.8 MeV,

m(Ξc(2939)0) = 2938.55± 0.21± 0.17± 0.14 MeV,

Γ(Ξc(2939)0) = 10.2± 0.8± 1.1 MeV,

m(Ξc(2965)0) = 2964.88± 0.26± 0.14± 0.14 MeV,

Γ(Ξc(2965)0) = 14.1± 0.9± 1.3 MeV,

where the uncertainties are statistical, systematic, and due to the limited knowledgeof the Λ+c mass. The Ξc(2923)

0 and Ξc(2939)0 baryons are new states. The

Ξc(2965)0 state is in the vicinity of the known Ξc(2970)

0 baryon; however, theirmasses and natural widths differ significantly.

Published in Phys. Rev. Lett. 124 (2020) 222001

c© 2020 CERN for the benefit of the LHCb collaboration. CC BY 4.0 licence.

†Authors are listed at the end of this paper.

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Singly charmed baryons are composed of a charm quark and two light quarks. Due tothe large mass difference between the charm and the lighter quarks, these baryons providean insight into the spectrum of states using symmetries described by the Heavy QuarkEffective Theory [1,2]. Numerous theoretical predictions of the properties of heavy baryons,containing either a charm or a beauty quark, have been made in recent years [3–13]. Inmany of these models, the heavy quark interacts with a lighter diquark, which is treatedas a single object. Other predictions are based on Lattice QCD calculations [14].

In 2017, the LHCb collaboration reported the observation of five new narrow Ω0cbaryons decaying to the Ξ+c K

− final state [15], four of which were later confirmed bythe Belle collaboration [16]. It is currently not understood why the natural widths ofthese resonances are small [17,18], although a similar trend has recently been observedin the excited Ω−b states decaying to Ξ

0bK− [19]. Investigating a different charmed mass

spectrum could lead to a better understanding of this feature.A natural extension to the Ξ+c K

− analysis is the study of the Λ+c K− spectrum. The

BaBar collaboration was the first to observe a structure in the Λ+c K− mass spectrum in

B−→ K−Λ+c Λ−c decays peaking at 2.93 GeV in 2007 [20]. However, it was not interpretedas a new state due to the absence of an amplitude analysis. Unless otherwise stated,charge-conjugate processes are implicitly included, and natural units with ~ = c = 1are used throughout. Later that year another analysis was published [21], looking atstrongly interacting prompt decays of charm-strange baryons to several final states, one ofwhich was Λ+c K

−. No resonances were reported in the Λ+c K− mass spectrum. The Belle

collaboration also reported the study of B−→ K−Λ+c Λ−c decays [22]. A peaking structurewas observed in the Λ+c K

− mass spectrum compatible with the results of Ref. [20] andinterpreted as a new Ξ0c baryon, dubbed Ξc(2930)

0. Similarly, evidence of the isospinpartner Ξc(2930)

+ in B0→ K0Λ+c Λ−c decays has been claimed [23].This letter presents a search for excited Ξ0c baryons, hereafter referred to as Ξ

∗∗0c , in

the Λ+c K− spectrum in a mass region around the Ξc(2930)

0 state, with the Λ+c baryonsreconstructed in the pK−π+ final state. Defining ∆M ≡ m(Λ+c K−)−m(Λ+c )−m(K−),the region considered is ∆M < 300 MeV. The data are collected in pp collisions withthe LHCb detector at a centre-of-mass energy of 13 TeV, corresponding to an integratedluminosity of 5.6 fb−1.

The LHCb detector [24, 25] is a single-arm forward spectrometer covering the pseu-dorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks.The detector elements that are particularly relevant to this analysis are: a silicon-stripvertex detector surrounding the pp interaction region that allows c and b hadrons to beidentified from their characteristically long flight distance; a tracking system that providesa measurement of the momentum of charged particles; and two ring-imaging Cherenkovdetectors that are able to discriminate between different species of charged hadrons. Theonline event selection is performed by a trigger, which consists of a hardware stage, basedon information from the calorimeter and muon systems, followed by a two-level softwarestage, which applies a full event reconstruction [26, 27]. Simulated data samples areproduced with the software packages described in Refs. [28–32] and are used to optimisethe selection requirements, to quantify the invariant-mass resolution, and to model physicsprocesses which may constitute peaking backgrounds in the analysis.

Candidate Λ+c baryons are formed from the combination of three tracks of good qualitywhich are inconsistent with originating from any primary proton-proton interactionvertex (PV) and have large transverse momentum (pT). Particle identification (PID)

1

requirements are imposed on all three tracks to suppress combinatorial background andmisidentified charm-meson decays. The Λ+c candidates are required to have pT > 2 GeVand are constrained to originate from the associated PV by requiring a small χ2IP, definedas the difference between the vertex-fit χ2 of the PV reconstructed with and without thecandidate in question. The Λ+c vertex must also be displaced from the associated PVsuch that the Λ+c decay time is longer than 0.3 ps. A multivariate classifier based on aboosted decision tree (BDT) algorithm [33,34] implemented in the TMVA toolkit [35] isused to further improve the Λ+c signal purity. The input variables given to the BDT arethe χ2 value of the Λ+c decay-vertex fit, the Λ

+c flight distance between the production

and decay vertex, the angle between the Λ+c momentum vector and the line that joinsthe Λ+c decay vertex with its associated PV, the χ

2IP and pT of the Λ

+c candidate, and the

χ2IP and PID responses of the Λ+c decay particles. The background sample used in the

BDT training consists of the lower and upper sidebands of the pK−π+ invariant massdistribution, 2230 − 2250 MeV and 2320 − 2340 MeV, respectively. The signal sampleused is the Λ+c sample in data after subtracting the background by means of the sP lottechnique [36], exploiting m(pK−π+) as discriminating variable. The training of themultivariate algorithm is carried out by using 20 000 candidates of the reconstructed Λ+ccandidates from the data recorded in 2016. The requirement on the BDT response isdetermined using 200 000 Λ+c candidates by maximising the figure of merit S/

√S +B,

where S is the Λ+c signal yield extracted from a fit to the mass spectrum of Λ+c candidates

passing a given BDT requirement and B is expected background yield. The value for Bis extrapolated by scaling the background yield over the full mass range of the fit to a±15 MeV mass range around the Λ+c peak.

Misidentified D+ → K−π+π+, D+ → K+K−π+ and D+s → K+K−π+ backgrounddecays are observed after changing the mass hypothesis of the proton into a kaon or a pion.These background components are reduced by employing a tighter PID selection andrequiring the invariant mass m(K+K−) to differ by at least 10 MeV from the known φ(1020)mass [37]. Removing all candidates in mass windows around the D+(s) mass distributionswould result in a large loss of signal efficiency and therefore is not implemented. However,it is checked that the results of the analysis are stable when these background componentsare removed fully. About 125 million Λ+c signal decays are selected for further analysis witha purity of 93%. The invariant-mass distribution of 20% of the Λ+c candidates satisfyingthese selection requirements is shown in Fig. 1.

The Ξ∗∗0c candidates are formed from Λ+c K

− combinations, where the Λ+c candidatemass is required to be within 20 MeV of the known Λ+c mass [37]. Each Λ

+c candidate is

combined with a K− candidate that is consistent with originating from the associatedPV. The Λ+c and K

− particles are fitted to a common vertex, which is required to beconsistent with the associated PV.

The main contribution to the combinatorial background in the Λ+c K− mass spectrum

is due to the large number of kaon candidates from the PV. The signal to background ratiois improved by optimising the PID criteria of the K− candidates and the pT requirementon the Ξ∗∗0c candidates using the figure of merit �/(

√BP + 5/2) [38]. Here, � is the

efficiency determined using simulated Ξc(2930)0→ Λ+c K− decays, and BP is the number

of Λ+c K− candidates in the mass region 260 < ∆M < 290 MeV, corresponding to the

background expected in a mass window around the expected Ξc(2930)0 signal, with width

Γ(Ξc(2930)0) = 26 ± 8 MeV [37]. Based on the optimisation above, the pT of the Ξ0c

candidates is required to be larger than 7350 MeV, and the kaon PID is required to satisfy

2

2250 2300 2350) [MeV]+π−Kp(m

0

200

400

600

800

1000310×

Can

dida

tes

/ (0.

5 M

eV)

LHCb

Figure 1: Distribution of the reconstructed invariant mass m(pK−π+) for 20% of the candidatesin the Λ+c sample passing the selection described in the text. The solid blue curve shows theresult of the fit, and the dashed blue line indicates the background component of the fit.

a tight criterion. The fraction of events with multiple candidates is found to be 0.88% inthe entire ∆M range. All candidates are included in the analysis.

The resulting ∆M distribution of the signal candidates is shown in Fig. 2, wherea fit to the data is superimposed. Three narrow structures are observed in the Λ+c K

−

candidate spectrum. These peaking structures are not seen in the wrong-sign (WS) Λ+c K+

candidates or Λ+c sideband distributions. The ∆M distribution also shows a broad structureto the left of the three narrow structures consistent with being partially reconstructedΞc(3055)→ Σc(2455)(→ Λ+c π)K− and Ξc(3080)→ Σc(2455)(→ Λ+c π)K− decays, wherethe pion is not reconstructed.

An unbinned maximum-likelihood fit, henceforth denoted the reference fit, is performedto the ∆M distribution to measure the parameters of each peak. The background ismodelled by an empirical function of the form ∆Ma × exp(−b × ∆M), where a andb vary freely. Each signal peak is described by an S-wave relativistic Breit−Wignerfunction convolved with a mass-resolution function. The experimental mass resolutionis determined using simulated Ξ∗∗0c → Λ+c K− decays at several Ξ∗∗0c masses. In the∆M interval where the three narrow peaks occur, the mass resolution varies between1.7 and 2.2 MeV. Simulated data are also generated to determine the shape of partiallyreconstructed Ξc(3055) and Ξc(3080) decays. The shapes of these contributions areallowed to shift in ∆M by the uncertainties in the decay-product masses, where theshift is Gaussian constrained. From isospin symmetry, the yields of the components areconstrained to be twice as large as the corresponding Ξc(3055)

0 and Ξc(3080)0 components.

The fit model outlined so far does not accurately describe the data in the mass regionclose to the kinematic threshold, and thus an additional component is considered. Thereare no known decays of Σc(2455)(→ Λ+c π)K− or Σc(2520)(→ Λ+c π)K− which could enterthe sample as partially reconstructed components at ∆M ' 0. It is observed that themissing component is consistent with being due to the partial reconstruction of the statethat peaks around ∆M ' 140 MeV when it decays directly to the Λ+c K−π+ final statewithout any intermediate resonance. The shape of these partially reconstructed decays istaken from simulated samples generated using the RapidSim package [39] and the yield isa free parameter in the fit.

The ∆M distribution with the fit to the data superimposed is shown in Fig. 2(a). The

3

0 100 200 300) [MeV]−K(m) - +cΛ(m) - −K+cΛ(m

0

500

1000

1500

2000C

andi

date

s / (

1 M

eV)

LHCb(a)

0 100 200 300) [MeV]−K(m) - +cΛ(m) - −K+cΛ(m

0

500

1000

1500

2000

Can

dida

tes

/ (1

MeV

)

LHCb(b)

−K+cΛ→0(2923)cΞ−K+cΛ→0(2939)cΞ−K+cΛ→0(2965)cΞ

+π−K+cΛ→+(2923)cΞ−K)+π+cΛ→(++cΣ→+(3055)cΞ

−K)0π+cΛ→(+cΣ→0(3055)cΞ−K)+π+cΛ→(++cΣ→+(3080)cΞ

−K)0π+cΛ→(+cΣ→0(3080)cΞBackgroundAdditional component

Figure 2: Distributions of the reconstructed invariant-mass difference∆M = m(Λ+c K

−)−m(Λ+c )−m(K−) for all candidates passing the selection require-ments described in the text. The black symbols show the selected signal candidates. The resultof a fit, described in the text, is overlaid (solid blue line). In plot (a) the reference fit is shown.Plot (b) shows an alternative description to the data, where an additional Gaussian componentgiven by the cyan dot-dashed line is added to the fit model around ∆M ' 100 MeV. Themissing child particles in the reconstruction are indicated in grey in the legend.

Table 1: Peak positions in the invariant-mass difference distribution ∆M , natural widths Γ,signal yields and local significances of the three mass peaks obtained from the fit to the Λ+c K

−

mass spectrum, where the systematic uncertainties are statistical.

Peak of ∆M [MeV] Γ [MeV] Signal yields142.91± 0.25 7.1± 0.8 5400± 400158.45± 0.21 10.2± 0.8 10400± 600184.75± 0.26 14.1± 0.9 11700± 600

goodness-of-fit value is χ2/ndof = 301/(300− 19) = 1.07, where ndof is the number of thedegrees of freedom. Table 1 shows the results for the parameters of the signal peaks ofthe reference fit, hereafter named Ξc(2923)

0, Ξc(2939)0 and Ξc(2965)

0.To validate the presence of the signal components and test the stability of the fit

parameters, several additional checks are performed. The data are fitted in samplesaccording to the year of data-taking and to different data-taking conditions depending onthe LHCb magnet configuration. The Λ+c K

− sample and its charge conjugate are alsostudied separately. The results are consistent among all samples.

The data and the reference fit show the least compatibility in the region around∆M ' 100 MeV. This may be due to a mismodelling of the partially reconstructeddistributions, but it could also be due to the presence of further new Ξ∗∗0c baryonstates. Figure 2(b) shows the ∆M distribution for the signal sample where an additionalcomponent, parametrized by an empirical Gaussian function, has been added to thereference fit. This fit has a goodness-of-fit value of χ2/ndof = 278/(300− 22) = 1.00. Asa cross-check, this structure is tested in subsamples of the data set divided by data-takingyear, and showed an inconsistency in the scaling of the yield with respect to the integratedluminosity. Furthermore, the feed-down components are highly suppressed when thiscontribution is included. More data are required to understand the cause of this additionalstructure. It is accounted for when calculating the systematic uncertainties.

4

Table 2: Summary of the contributions to the systematic uncertainties on the resonanceparameters. Absolute deviations from the nominal fit are quoted.

Source Ξc(2923)0 Ξc(2939)

0 Ξc(2965)0

m [MeV] Γ [MeV] m [MeV] Γ [MeV] m [MeV] Γ [MeV]Alternative fit model 0.15 1.6 0.14 0.4 0.04 1.1Resonance interferences 0.08 0.7 0.06 1.0 0.11 0.7Momentum-scale 0.04 – 0.05 – 0.06 –Energy losses 0.04 – 0.04 – 0.04 –Resolution calibration – 0.6 – 0.2 – 0.3Total 0.20 1.8 0.17 1.1 0.14 1.3

Several sources of systematic uncertainty may affect the measured parameters. Thefit model uncertainty is evaluated by replacing the background model by an alternativefunction, consisting of a combination of the wrong-sign m(Λ+c K

+) invariant-mass distri-bution shape and the shape obtained from candidates in the Λ+c sideband. In addition,the choice of the relativistic Breit−Wigner model is changed by setting the values ofthe angular momentum L between the child particles to L = 1, 2 and separately varyingthe Blatt−Weisskopf factors [40] from 2 to 4 GeV−1. Furthermore, the fit is adaptedto include any partially reconstructed decays Ξ∗∗c → Σc(2455/2520)(→ Λ+c π)K− thatare found to not contribute significantly to the reference fit. Finally, deviations in fitparameters between the reference fit and the fit shown in Fig. 2(b) are included in the fitmodel uncertainty. The largest deviation from the reference fit is quoted as the systematicuncertainty for the fit model. Resonances with the same spin-parity that are close inmass can interfere. An interference term is introduced between neighbouring resonances,for one pair of resonances at a time. With the interference term, the lineshape takesthe form A = |cjBWj + ckBWkeiφ|2 where j and k denote the two resonances, BWj,k areBreit−Wigner functions and cj,k and φ are free real parameters. The largest differencebetween the reference fit and a fit where resonance interference is allowed is used as thesystematic uncertainty. In addition, several other sources of systematic uncertainty onlyaffect the mass measurement. These include the momentum-scale uncertainty, evaluatedby shifting the momentum-scale of charged tracks by ±0.03% [41] in simulated decays,and the imperfect modelling of the energy loss in the detector material, resulting in asystematic uncertainty of 0.04 MeV [42]. Finally, a systematic uncertainty is attributed tothe width measurement, to account for the fact that the simulation may not reproduce theabsolute mass resolution perfectly. The corresponding systematic uncertainty is obtainedby the change in the width when the value of the resolution, determined on simulateddata, is varied by 10% [43]. The systematic uncertainties are summarised in Table 2 andin Table 3 their measured masses and natural widths are summarised.

The observations described in this letter and the lack of any Ξc(2930)0 signal

indicates that the broad bump observed in B− → K−Λ+c Λ−c decays [20, 22] mightbe due to the overlap of two narrower states, such as the Ξc(2923)

0 and Ξc(2939)0

baryons. The Ξc(2965)0 baryon is in the vicinity of the known Ξc(2970)

0 baryon,which has been observed in different decay modes, Σc(2455)

0K0S [21], Ξ′c+π− [44] and

Ξc(2645)+π− [45]. Furthermore, the Ξc(2965)

0 resonance has a natural width and masswhich differs significantly from that of the Ξc(2970)

0 baryon, Γ(Ξc(2970)0) = 28.1+3.4−4.0 MeV

5

Table 3: Summary of the parameters for the studied states, showing the measured ∆M values, themasses and the natural widths, where the first uncertainty is statistical and the second uncertaintyis systematic. For the mass measurement, the third uncertainty denotes the uncertainty on theknown Λ+c mass [37].

Resonance Peak of ∆M [MeV] Mass [MeV] Γ [MeV]Ξc(2923)

0 142.91± 0.25± 0.20 2923.04± 0.25± 0.20± 0.14 7.1± 0.8± 1.8Ξc(2939)

0 158.45± 0.21± 0.17 2938.55± 0.21± 0.17± 0.14 10.2± 0.8± 1.1Ξc(2965)

0 184.75± 0.26± 0.14 2964.88± 0.26± 0.14± 0.14 14.1± 0.9± 1.3

and m(Ξc(2970)0) = 2967.8+0.9−0.7 MeV [37]. Further studies are required to establish whether

the Ξc(2965)0 state is indeed a different baryon. The equal spacing rule [46,47] succeeded

to predict the mass of the Ω baryon and holds for other flavour multiplets such as thesextet of the JP = 3/2+ charmed ground states:

m(Ωc(2770)0)−m(Ξc(2645)0) ' m(Ξc(2645)0)−m(Σc(2520)0) ' 125 MeV.

It is noted that the rule also seems to hold for the Ξc(2923)0, Ξc(2939)

0 and Ξc(2965)0

baryons within a precision of a few MeV:

m(Ωc(3050)0)−m(Ξc(2923)0) ' m(Ξc(2923)0)−m(Σc(2800)0) ' 125 MeV,

m(Ωc(3065)0)−m(Ξc(2939)0) ' 125 MeV,

m(Ωc(3090)0)−m(Ξc(2965)0) ' 125 MeV.

This pattern may indicate that the new states reported in this analysis are related to theexcited Ω0c baryons observed in the Ξ

+c K

− spectrum. Measurements of spin-parities willbe crucial to confirm whether they belong to the same flavour multiplets.

In summary, pp collision data collected by the LHCb experiment at a centre-of-massenergy of 13 TeV, corresponding to an integrated luminosity of 5.6 fb−1, are used to searchfor excited Ξ0c resonances in the Λ

+c K

− mass spectrum. Three different Ξ0c baryons,Ξc(2923)

0, Ξc(2939)0 and Ξc(2965)

0, are unambiguously observed. The two baryons atlower mass are observed for the first time, while an investigation of additional final statesis required to establish whether the Ξc(2965)

0 and Ξc(2970)0 states are different baryons.

Acknowledgements

We express our gratitude to our colleagues in the CERN accelerator departments for theexcellent performance of the LHC. We thank the technical and administrative staff at theLHCb institutes. We acknowledge support from CERN and from the national agencies:CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3(France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSWand NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF andSER (Switzerland); NASU (Ukraine); STFC (United Kingdom); DOE NP and NSF (USA).We acknowledge the computing resources that are provided by CERN, IN2P3 (France),KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP

6

(United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH(Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted tothe communities behind the multiple open-source software packages on which we depend.Individual groups or members have received support from AvH Foundation (Germany);EPLANET, Marie Sk lodowska-Curie Actions and ERC (European Union); ANR, LabexP2IO and OCEVU, and Région Auvergne-Rhône-Alpes (France); Key Research Programof Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China);RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); theRoyal Society and the Leverhulme Trust (United Kingdom).

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LHCb collaboration

R. Aaij31, C. Abellán Beteta49, T. Ackernley59, B. Adeva45, M. Adinolfi53, H. Afsharnia9,C.A. Aidala81, S. Aiola25, Z. Ajaltouni9, S. Akar66, J. Albrecht14, F. Alessio47, M. Alexander58,A. Alfonso Albero44, G. Alkhazov37, P. Alvarez Cartelle60, A.A. Alves Jr45, S. Amato2,Y. Amhis11, L. An21, L. Anderlini21, G. Andreassi48, M. Andreotti20, F. Archilli16,A. Artamonov43, M. Artuso67, K. Arzymatov41, E. Aslanides10, M. Atzeni49, B. Audurier11,S. Bachmann16, J.J. Back55, S. Baker60, V. Balagura11,b, W. Baldini20, J. Baptista Leite1,R.J. Barlow61, S. Barsuk11, W. Barter60, M. Bartolini23,47,h, F. Baryshnikov78, J.M. Basels13,G. Bassi28, V. Batozskaya35, B. Batsukh67, A. Battig14, A. Bay48, M. Becker14, F. Bedeschi28,I. Bediaga1, A. Beiter67, V. Belavin41, S. Belin26, V. Bellee48, K. Belous43, I. Belyaev38,G. Bencivenni22, E. Ben-Haim12, S. Benson31, A. Berezhnoy39, R. Bernet49, D. Berninghoff16,H.C. Bernstein67, C. Bertella47, E. Bertholet12, A. Bertolin27, C. Betancourt49, F. Betti19,e,M.O. Bettler54, Ia. Bezshyiko49, S. Bhasin53, J. Bhom33, M.S. Bieker14, S. Bifani52, P. Billoir12,A. Bizzeti21,t, M. Bjørn62, M.P. Blago47, T. Blake55, F. Blanc48, S. Blusk67, D. Bobulska58,V. Bocci30, O. Boente Garcia45, T. Boettcher63, A. Boldyrev79, A. Bondar42,w, N. Bondar37,47,S. Borghi61, M. Borisyak41, M. Borsato16, J.T. Borsuk33, T.J.V. Bowcock59, A. Boyer47,C. Bozzi20, M.J. Bradley60, S. Braun65, A. Brea Rodriguez45, M. Brodski47, J. Brodzicka33,A. Brossa Gonzalo55, D. Brundu26, E. Buchanan53, A. Büchler-Germann49, A. Buonaura49,C. Burr47, A. Bursche26, A. Butkevich40, J.S. Butter31, J. Buytaert47, W. Byczynski47,S. Cadeddu26, H. Cai72, R. Calabrese20,g, L. Calero Diaz22, S. Cali22, R. Calladine52,M. Calvi24,i, M. Calvo Gomez44,l, P. Camargo Magalhaes53, A. Camboni44,l, P. Campana22,D.H. Campora Perez31, A.F. Campoverde Quezada5, L. Capriotti19,e, A. Carbone19,e,G. Carboni29, R. Cardinale23,h, A. Cardini26, I. Carli6, P. Carniti24,i, K. Carvalho Akiba31,A. Casais Vidal45, G. Casse59, M. Cattaneo47, G. Cavallero47, S. Celani48, R. Cenci28,o,J. Cerasoli10, M.G. Chapman53, M. Charles12, Ph. Charpentier47, G. Chatzikonstantinidis52,M. Chefdeville8, V. Chekalina41, C. Chen3, S. Chen26, A. Chernov33, S.-G. Chitic47,V. Chobanova45, S. Cholak48, M. Chrzaszcz33, A. Chubykin37, V. Chulikov37, P. Ciambrone22,M.F. Cicala55, X. Cid Vidal45, G. Ciezarek47, F. Cindolo19, P.E.L. Clarke57, M. Clemencic47,H.V. Cliff54, J. Closier47, J.L. Cobbledick61, V. Coco47, J.A.B. Coelho11, J. Cogan10,E. Cogneras9, L. Cojocariu36, P. Collins47, T. Colombo47, A. Contu26, N. Cooke52,G. Coombs58, S. Coquereau44, G. Corti47, C.M. Costa Sobral55, B. Couturier47, D.C. Craik63,J. Crkovská66, A. Crocombe55, M. Cruz Torres1,z, R. Currie57, C.L. Da Silva66, E. Dall’Occo14,J. Dalseno45,53, C. D’Ambrosio47, A. Danilina38, P. d’Argent47, A. Davis61,O. De Aguiar Francisco47, K. De Bruyn47, S. De Capua61, M. De Cian48, J.M. De Miranda1,L. De Paula2, M. De Serio18,d, P. De Simone22, J.A. de Vries76, C.T. Dean66, W. Dean81,D. Decamp8, L. Del Buono12, B. Delaney54, H.-P. Dembinski14, A. Dendek34, V. Denysenko49,D. Derkach79, O. Deschamps9, F. Desse11, F. Dettori26,f , B. Dey7, A. Di Canto47, P. Di Nezza22,S. Didenko78, H. Dijkstra47, V. Dobishuk51, F. Dordei26, M. Dorigo28,x, A.C. dos Reis1,L. Douglas58, A. Dovbnya50, K. Dreimanis59, M.W. Dudek33, L. Dufour47, P. Durante47,J.M. Durham66, D. Dutta61, M. Dziewiecki16, A. Dziurda33, A. Dzyuba37, S. Easo56,U. Egede69, V. Egorychev38, S. Eidelman42,w, S. Eisenhardt57, S. Ek-In48, L. Eklund58, S. Ely67,A. Ene36, E. Epple66, S. Escher13, J. Eschle49, S. Esen31, T. Evans47, A. Falabella19, J. Fan3,Y. Fan5, N. Farley52, S. Farry59, D. Fazzini11, P. Fedin38, M. Féo47, P. Fernandez Declara47,A. Fernandez Prieto45, F. Ferrari19,e, L. Ferreira Lopes48, F. Ferreira Rodrigues2,S. Ferreres Sole31, M. Ferrillo49, M. Ferro-Luzzi47, S. Filippov40, R.A. Fini18, M. Fiorini20,g,M. Firlej34, K.M. Fischer62, C. Fitzpatrick61, T. Fiutowski34, F. Fleuret11,b, M. Fontana47,F. Fontanelli23,h, R. Forty47, V. Franco Lima59, M. Franco Sevilla65, M. Frank47, C. Frei47,D.A. Friday58, J. Fu25,p, Q. Fuehring14, W. Funk47, E. Gabriel57, T. Gaintseva41,A. Gallas Torreira45, D. Galli19,e, S. Gallorini27, S. Gambetta57, Y. Gan3, M. Gandelman2,

11

P. Gandini25, Y. Gao4, L.M. Garcia Martin46, J. Garćıa Pardiñas49, B. Garcia Plana45,F.A. Garcia Rosales11, L. Garrido44, D. Gascon44, C. Gaspar47, D. Gerick16, E. Gersabeck61,M. Gersabeck61, T. Gershon55, D. Gerstel10, Ph. Ghez8, V. Gibson54, A. Gioventù45,P. Gironella Gironell44, L. Giubega36, C. Giugliano20, K. Gizdov57, V.V. Gligorov12, C. Göbel70,E. Golobardes44,l, D. Golubkov38, A. Golutvin60,78, A. Gomes1,a, P. Gorbounov38,I.V. Gorelov39, C. Gotti24,i, E. Govorkova31, J.P. Grabowski16, R. Graciani Diaz44,T. Grammatico12, L.A. Granado Cardoso47, E. Graugés44, E. Graverini48, G. Graziani21,A. Grecu36, R. Greim31, P. Griffith20, L. Grillo61, L. Gruber47, B.R. Gruberg Cazon62, C. Gu3,M. Guarise20, E. Gushchin40, A. Guth13, Yu. Guz43,47, T. Gys47, P. A. Gnther16,T. Hadavizadeh62, G. Haefeli48, C. Haen47, S.C. Haines54, P.M. Hamilton65, Q. Han7, X. Han16,T.H. Hancock62, S. Hansmann-Menzemer16, N. Harnew62, T. Harrison59, R. Hart31, C. Hasse14,M. Hatch47, J. He5, M. Hecker60, K. Heijhoff31, K. Heinicke14, A.M. Hennequin47,K. Hennessy59, L. Henry25,46, J. Heuel13, A. Hicheur68, D. Hill62, M. Hilton61, P.H. Hopchev48,J. Hu16, J. Hu71, W. Hu7, W. Huang5, W. Hulsbergen31, T. Humair60, R.J. Hunter55,M. Hushchyn79, D. Hutchcroft59, D. Hynds31, P. Ibis14, M. Idzik34, P. Ilten52, A. Inglessi37,K. Ivshin37, R. Jacobsson47, S. Jakobsen47, E. Jans31, B.K. Jashal46, A. Jawahery65,V. Jevtic14, F. Jiang3, M. John62, D. Johnson47, C.R. Jones54, B. Jost47, N. Jurik62,S. Kandybei50, M. Karacson47, J.M. Kariuki53, N. Kazeev79, M. Kecke16, F. Keizer54,47,M. Kelsey67, M. Kenzie55, T. Ketel32, B. Khanji47, A. Kharisova80, K.E. Kim67, T. Kirn13,V.S. Kirsebom48, S. Klaver22, K. Klimaszewski35, S. Koliiev51, A. Kondybayeva78,A. Konoplyannikov38, P. Kopciewicz34, R. Kopecna16, P. Koppenburg31, M. Korolev39,I. Kostiuk31,51, O. Kot51, S. Kotriakhova37, L. Kravchuk40, R.D. Krawczyk47, M. Kreps55,F. Kress60, S. Kretzschmar13, P. Krokovny42,w, W. Krupa34, W. Krzemien35, W. Kucewicz33,k,M. Kucharczyk33, V. Kudryavtsev42,w, H.S. Kuindersma31, G.J. Kunde66, T. Kvaratskheliya38,D. Lacarrere47, G. Lafferty61, A. Lai26, D. Lancierini49, J.J. Lane61, G. Lanfranchi22,C. Langenbruch13, O. Lantwin49,78, T. Latham55, F. Lazzari28,u, R. Le Gac10, S.H. Lee81,R. Lefèvre9, A. Leflat39,47, O. Leroy10, T. Lesiak33, B. Leverington16, H. Li71, L. Li62, X. Li66,Y. Li6, Z. Li67, X. Liang67, T. Lin60, R. Lindner47, V. Lisovskyi14, G. Liu71, X. Liu3, D. Loh55,A. Loi26, J. Lomba Castro45, I. Longstaff58, J.H. Lopes2, G. Loustau49, G.H. Lovell54, Y. Lu6,D. Lucchesi27,n, M. Lucio Martinez31, Y. Luo3, A. Lupato61, E. Luppi20,g, O. Lupton55,A. Lusiani28,s, X. Lyu5, S. Maccolini19,e, F. Machefert11, F. Maciuc36, V. Macko48,P. Mackowiak14, S. Maddrell-Mander53, L.R. Madhan Mohan53, O. Maev37, A. Maevskiy79,D. Maisuzenko37, M.W. Majewski34, S. Malde62, B. Malecki47, A. Malinin77, T. Maltsev42,w,H. Malygina16, G. Manca26,f , G. Mancinelli10, R. Manera Escalero44, D. Manuzzi19,e,D. Marangotto25,p, J. Maratas9,v, J.F. Marchand8, U. Marconi19, S. Mariani21,47,21,C. Marin Benito11, M. Marinangeli48, P. Marino48, J. Marks16, P.J. Marshall59, G. Martellotti30,L. Martinazzoli47, M. Martinelli24,i, D. Martinez Santos45, F. Martinez Vidal46, A. Massafferri1,M. Materok13, R. Matev47, A. Mathad49, Z. Mathe47, V. Matiunin38, C. Matteuzzi24,K.R. Mattioli81, A. Mauri49, E. Maurice11,b, M. McCann60, L. Mcconnell17, A. McNab61,R. McNulty17, J.V. Mead59, B. Meadows64, C. Meaux10, G. Meier14, N. Meinert74,D. Melnychuk35, S. Meloni24,i, M. Merk31, A. Merli25, L. Meyer Garcia2, M. Mikhasenko47,D.A. Milanes73, E. Millard55, M.-N. Minard8, O. Mineev38, L. Minzoni20, S.E. Mitchell57,B. Mitreska61, D.S. Mitzel47, A. Mödden14, A. Mogini12, R.D. Moise60, T. Mombächer14,I.A. Monroy73, S. Monteil9, M. Morandin27, G. Morello22, M.J. Morello28,s, J. Moron34,A.B. Morris10, A.G. Morris55, R. Mountain67, H. Mu3, F. Muheim57, M. Mukherjee7,M. Mulder47, D. Müller47, K. Müller49, C.H. Murphy62, D. Murray61, P. Muzzetto26, P. Naik53,T. Nakada48, R. Nandakumar56, T. Nanut48, I. Nasteva2, M. Needham57, I. Neri20, N. Neri25,p,S. Neubert16, N. Neufeld47, R. Newcombe60, T.D. Nguyen48, C. Nguyen-Mau48,m, E.M. Niel11,S. Nieswand13, N. Nikitin39, N.S. Nolte47, C. Nunez81, A. Oblakowska-Mucha34, V. Obraztsov43,S. Ogilvy58, D.P. O’Hanlon53, R. Oldeman26,f , C.J.G. Onderwater75, J. D. Osborn81,

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A. Ossowska33, J.M. Otalora Goicochea2, T. Ovsiannikova38, P. Owen49, A. Oyanguren46,P.R. Pais48, T. Pajero28,47,28,s, A. Palano18, M. Palutan22, G. Panshin80, A. Papanestis56,M. Pappagallo57, L.L. Pappalardo20, C. Pappenheimer64, W. Parker65, C. Parkes61,C.J. Parkinson45, G. Passaleva21,47, A. Pastore18, M. Patel60, C. Patrignani19,e, A. Pearce47,A. Pellegrino31, M. Pepe Altarelli47, S. Perazzini19, D. Pereima38, P. Perret9, K. Petridis53,A. Petrolini23,h, A. Petrov77, S. Petrucci57, M. Petruzzo25,p, B. Pietrzyk8, G. Pietrzyk48,M. Pili62, D. Pinci30, J. Pinzino47, F. Pisani19, A. Piucci16, V. Placinta36, S. Playfer57,J. Plews52, M. Plo Casasus45, F. Polci12, M. Poli Lener22, M. Poliakova67, A. Poluektov10,N. Polukhina78,c, I. Polyakov67, E. Polycarpo2, G.J. Pomery53, S. Ponce47, A. Popov43,D. Popov52, S. Poslavskii43, K. Prasanth33, L. Promberger47, C. Prouve45, V. Pugatch51,A. Puig Navarro49, H. Pullen62, G. Punzi28,o, W. Qian5, J. Qin5, R. Quagliani12, B. Quintana8,N.V. Raab17, R.I. Rabadan Trejo10, B. Rachwal34, J.H. Rademacker53, M. Rama28,M. Ramos Pernas45, M.S. Rangel2, F. Ratnikov41,79, G. Raven32, M. Reboud8, F. Redi48,F. Reiss12, C. Remon Alepuz46, Z. Ren3, V. Renaudin62, S. Ricciardi56, D.S. Richards56,S. Richards53, K. Rinnert59, P. Robbe11, A. Robert12, A.B. Rodrigues48, E. Rodrigues59,J.A. Rodriguez Lopez73, M. Roehrken47, A. Rollings62, V. Romanovskiy43, M. Romero Lamas45,A. Romero Vidal45, J.D. Roth81, M. Rotondo22, M.S. Rudolph67, T. Ruf47, J. Ruiz Vidal46,A. Ryzhikov79, J. Ryzka34, J.J. Saborido Silva45, N. Sagidova37, N. Sahoo55, B. Saitta26,f ,C. Sanchez Gras31, C. Sanchez Mayordomo46, R. Santacesaria30, C. Santamarina Rios45,M. Santimaria22, E. Santovetti29,j , G. Sarpis61, M. Sarpis16, A. Sarti30, C. Satriano30,r,A. Satta29, M. Saur5, D. Savrina38,39, L.G. Scantlebury Smead62, S. Schael13, M. Schellenberg14,M. Schiller58, H. Schindler47, M. Schmelling15, T. Schmelzer14, B. Schmidt47, O. Schneider48,A. Schopper47, H.F. Schreiner64, M. Schubiger31, S. Schulte48, M.H. Schune11, R. Schwemmer47,B. Sciascia22, A. Sciubba22, S. Sellam68, A. Semennikov38, A. Sergi52,47, N. Serra49,J. Serrano10, L. Sestini27, A. Seuthe14, P. Seyfert47, D.M. Shangase81, M. Shapkin43,L. Shchutska48, T. Shears59, L. Shekhtman42,w, V. Shevchenko77, E. Shmanin78,J.D. Shupperd67, B.G. Siddi20, R. Silva Coutinho49, L. Silva de Oliveira2, G. Simi27,n,S. Simone18,d, I. Skiba20, N. Skidmore16, T. Skwarnicki67, M.W. Slater52, J.G. Smeaton54,A. Smetkina38, E. Smith13, I.T. Smith57, M. Smith60, A. Snoch31, M. Soares19,L. Soares Lavra9, M.D. Sokoloff64, F.J.P. Soler58, B. Souza De Paula2, B. Spaan14,E. Spadaro Norella25,p, P. Spradlin58, F. Stagni47, M. Stahl64, S. Stahl47, P. Stefko48,O. Steinkamp49,78, S. Stemmle16, O. Stenyakin43, M. Stepanova37, H. Stevens14, S. Stone67,S. Stracka28, M.E. Stramaglia48, M. Straticiuc36, S. Strokov80, J. Sun26, L. Sun72, Y. Sun65,P. Svihra61, K. Swientek34, A. Szabelski35, T. Szumlak34, M. Szymanski47, S. Taneja61,Z. Tang3, T. Tekampe14, F. Teubert47, E. Thomas47, K.A. Thomson59, M.J. Tilley60,V. Tisserand9, S. T’Jampens8, M. Tobin6, S. Tolk47, L. Tomassetti20,g, D. Torres Machado1,D.Y. Tou12, E. Tournefier8, M. Traill58, M.T. Tran48, E. Trifonova78, C. Trippl48,A. Tsaregorodtsev10, G. Tuci28,o, A. Tully48, N. Tuning31, A. Ukleja35, A. Usachov31,A. Ustyuzhanin41,79, U. Uwer16, A. Vagner80, V. Vagnoni19, A. Valassi47, G. Valenti19,M. van Beuzekom31, H. Van Hecke66, E. van Herwijnen47, C.B. Van Hulse17, M. van Veghel75,R. Vazquez Gomez44, P. Vazquez Regueiro45, C. Vázquez Sierra31, S. Vecchi20, J.J. Velthuis53,M. Veltri21,q, A. Venkateswaran67, M. Veronesi31, M. Vesterinen55, J.V. Viana Barbosa47,D. Vieira64, M. Vieites Diaz48, H. Viemann74, X. Vilasis-Cardona44,l, G. Vitali28,A. Vitkovskiy31, A. Vollhardt49, D. Vom Bruch12, A. Vorobyev37, V. Vorobyev42,w,N. Voropaev37, R. Waldi74, J. Walsh28, J. Wang3, J. Wang72, J. Wang6, M. Wang3, Y. Wang7,Z. Wang49, D.R. Ward54, H.M. Wark59, N.K. Watson52, D. Websdale60, A. Weiden49,C. Weisser63, B.D.C. Westhenry53, D.J. White61, M. Whitehead53, D. Wiedner14,G. Wilkinson62, M. Wilkinson67, I. Williams54, M. Williams63, M.R.J. Williams61,T. Williams52, F.F. Wilson56, W. Wislicki35, M. Witek33, L. Witola16, G. Wormser11,S.A. Wotton54, H. Wu67, K. Wyllie47, Z. Xiang5, D. Xiao7, Y. Xie7, H. Xing71, A. Xu4, J. Xu5,

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L. Xu3, M. Xu7, Q. Xu5, Z. Xu4, Z. Xu5, Z. Yang3, Z. Yang65, Y. Yao67, L.E. Yeomans59,H. Yin7, J. Yu7, X. Yuan67, O. Yushchenko43, K.A. Zarebski52, M. Zavertyaev15,c, M. Zdybal33,M. Zeng3, D. Zhang7, L. Zhang3, S. Zhang4, W.C. Zhang3,y, Y. Zhang47, A. Zhelezov16,Y. Zheng5, X. Zhou5, Y. Zhou5, X. Zhu3, V. Zhukov13,39, J.B. Zonneveld57, S. Zucchelli19,e.

1Centro Brasileiro de Pesquisas F́ısicas (CBPF), Rio de Janeiro, Brazil2Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil3Center for High Energy Physics, Tsinghua University, Beijing, China4School of Physics State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing,China5University of Chinese Academy of Sciences, Beijing, China6Institute Of High Energy Physics (IHEP), Beijing, China7Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China8Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IN2P3-LAPP, Annecy, France9Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France10Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France11Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France12LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France13I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany14Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany15Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany16Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany17School of Physics, University College Dublin, Dublin, Ireland18INFN Sezione di Bari, Bari, Italy19INFN Sezione di Bologna, Bologna, Italy20INFN Sezione di Ferrara, Ferrara, Italy21INFN Sezione di Firenze, Firenze, Italy22INFN Laboratori Nazionali di Frascati, Frascati, Italy23INFN Sezione di Genova, Genova, Italy24INFN Sezione di Milano-Bicocca, Milano, Italy25INFN Sezione di Milano, Milano, Italy26INFN Sezione di Cagliari, Monserrato, Italy27INFN Sezione di Padova, Padova, Italy28INFN Sezione di Pisa, Pisa, Italy29INFN Sezione di Roma Tor Vergata, Roma, Italy30INFN Sezione di Roma La Sapienza, Roma, Italy31Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands32Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam,Netherlands33Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland34AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science,Kraków, Poland35National Center for Nuclear Research (NCBJ), Warsaw, Poland36Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania37Petersburg Nuclear Physics Institute NRC Kurchatov Institute (PNPI NRC KI), Gatchina, Russia38Institute of Theoretical and Experimental Physics NRC Kurchatov Institute (ITEP NRC KI), Moscow,Russia, Moscow, Russia39Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia40Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS), Moscow, Russia41Yandex School of Data Analysis, Moscow, Russia42Budker Institute of Nuclear Physics (SB RAS), Novosibirsk, Russia43Institute for High Energy Physics NRC Kurchatov Institute (IHEP NRC KI), Protvino, Russia,Protvino, Russia44ICCUB, Universitat de Barcelona, Barcelona, Spain45Instituto Galego de F́ısica de Altas Enerx́ıas (IGFAE), Universidade de Santiago de Compostela,Santiago de Compostela, Spain

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46Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia - CSIC, Valencia, Spain47European Organization for Nuclear Research (CERN), Geneva, Switzerland48Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland49Physik-Institut, Universität Zürich, Zürich, Switzerland50NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine51Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine52University of Birmingham, Birmingham, United Kingdom53H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom54Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom55Department of Physics, University of Warwick, Coventry, United Kingdom56STFC Rutherford Appleton Laboratory, Didcot, United Kingdom57School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom58School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom59Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom60Imperial College London, London, United Kingdom61Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom62Department of Physics, University of Oxford, Oxford, United Kingdom63Massachusetts Institute of Technology, Cambridge, MA, United States64University of Cincinnati, Cincinnati, OH, United States65University of Maryland, College Park, MD, United States66Los Alamos National Laboratory (LANL), Los Alamos, United States67Syracuse University, Syracuse, NY, United States68Laboratory of Mathematical and Subatomic Physics , Constantine, Algeria, associated to 269School of Physics and Astronomy, Monash University, Melbourne, Australia, associated to 5570Pontif́ıcia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil, associated to 271Guangdong Provencial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South ChinaNormal University, Guangzhou, China, associated to 372School of Physics and Technology, Wuhan University, Wuhan, China, associated to 373Departamento de Fisica , Universidad Nacional de Colombia, Bogota, Colombia, associated to 1274Institut für Physik, Universität Rostock, Rostock, Germany, associated to 1675Van Swinderen Institute, University of Groningen, Groningen, Netherlands, associated to 3176Universiteit Maastricht, Maastricht, Netherlands, associated to 3177National Research Centre Kurchatov Institute, Moscow, Russia, associated to 3878National University of Science and Technology “MISIS”, Moscow, Russia, associated to 3879National Research University Higher School of Economics, Moscow, Russia, associated to 4180National Research Tomsk Polytechnic University, Tomsk, Russia, associated to 3881University of Michigan, Ann Arbor, United States, associated to 67

aUniversidade Federal do Triângulo Mineiro (UFTM), Uberaba-MG, BrazilbLaboratoire Leprince-Ringuet, Palaiseau, FrancecP.N. Lebedev Physical Institute, Russian Academy of Science (LPI RAS), Moscow, RussiadUniversità di Bari, Bari, ItalyeUniversità di Bologna, Bologna, ItalyfUniversità di Cagliari, Cagliari, ItalygUniversità di Ferrara, Ferrara, ItalyhUniversità di Genova, Genova, ItalyiUniversità di Milano Bicocca, Milano, ItalyjUniversità di Roma Tor Vergata, Roma, ItalykAGH - University of Science and Technology, Faculty of Computer Science, Electronics andTelecommunications, Kraków, PolandlDS4DS, La Salle, Universitat Ramon Llull, Barcelona, SpainmHanoi University of Science, Hanoi, VietnamnUniversità di Padova, Padova, ItalyoUniversità di Pisa, Pisa, ItalypUniversità degli Studi di Milano, Milano, ItalyqUniversità di Urbino, Urbino, ItalyrUniversità della Basilicata, Potenza, Italy

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sScuola Normale Superiore, Pisa, ItalytUniversità di Modena e Reggio Emilia, Modena, ItalyuUniversità di Siena, Siena, ItalyvMSU - Iligan Institute of Technology (MSU-IIT), Iligan, PhilippineswNovosibirsk State University, Novosibirsk, RussiaxINFN Sezione di Trieste, Trieste, ItalyySchool of Physics and Information Technology, Shaanxi Normal University (SNNU), Xi’an, ChinazUniversidad Nacional Autonoma de Honduras, Tegucigalpa, Honduras

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References